With Kevin Garnett and Paul Pierce returning to TD Garden Sunday for the first time since they were traded to Brooklyn last summer, the Globe spoke with Celtics president of basketball operations Danny Ainge about the blockbuster swap that sent two icons to a division rival while giving the Celtics valuable assets to help speed up their rebuilding process. To recap, the Celtics traded Garnett, Pierce, Jason Terry, and D.J. White to the Nets for Gerald Wallace, Kris Humphries, MarShon Brooks, Kris Joseph, Keith Bogans, and three first-round draft picks (2014, 2016, and 2018), as well as the right to swap first-round picks in 2017.

How did the deal come together?

It did come together fairly quickly. What I was excited about was that it appeared at the time to be a great situation for everybody — I think that for Paul and KG and Jason Terry and for us. It looked like it was going to be a good situation for them to be a major contender again and be vying for a championship. Their year hasn’t gone that way, but before the season started, it sure looked like it. I think it was a happy way to make a very difficult decision.

You had intimated before that the real key in such a deal was Nets owner Mikhail Prokhorov, a Russian billionaire who was hell-bent on winning a title, no matter the cost. What did you mean?

It took an owner that was willing to go deep into the luxury tax, sure, for those guys to remain together. (Note: Prokhorov will be paying approximately $183 million for his team’s roster this season, including roughly $82 million in luxury taxes, a league record. The previous high for an NBA team’s luxury-tax bill is said to be Portland’s nearly $52 million in 2002-03.)

Kevin McHale recently said the state of the NBA under its new collective bargaining agreement kind of forces you to make a deal like this even if you would have liked Paul to retire a Celtic. Is that fair?

Well, I don’t know if it forces it, but it forces it if you want to remain competitive. And it certainly gives you a jumpstart in the rebuilding process, as opposed to not doing it for sentimental reasons. I think what Kevin is saying is, nobody wants to trade away a Paul Pierce or a Kevin Garnett — and Jason Terry, for that matter. Jason Terry, he only played with us for a year, but I love that guy. He gave a lot to us and he’s just a class act — throughout his career. But that’s nothing that anybody wants to do, and is looking forward to doing. But I think that when the opportunity presented itself, it was a deal that I had to do for the franchise.

How has it been for you watching them from afar, given how their season has gone?

I’ve been frustrated for them. I know that they’ve had a lot of injuries, like to Deron Williams . . . I thought [Pierce and Garnett] were going to play complementary roles to [Brook] Lopez, Joe Johnson, and Deron Williams. But arguably their two best players [Williams and Lopez] have been out for most of the year, and it’s been a real challenge. I think that’s the single reason why their team has struggled on the court and their record is what it is — because of the injuries to their two best players.

People say you pulled off a huge steal. What do you think when you hear that?

Well, what I felt at the time was, I thought it was a really gutsy move by Brooklyn. I admired it. I thought the way KG finished last year, and Paul — both of them looked like they had a lot of basketball left in them, as the season finished last year. And so, I felt that it was a good deal for both teams. Like, I wasn’t able to put Joe Johnson and Deron Williams and Brook Lopez around Paul and KG. I wish I could have. They still would’ve been Celtics. But we weren’t in that position, to become a contender, I don’t think. I didn’t think that Paul and KG could carry us like they had for the five or six years previous. We were a team, I felt, that was destined to mediocrity as opposed to excellence with those guys. And especially with [Rajon] Rondo being out and so forth, it was going to be a long year for us with those two guys at the stage of their careers. It wouldn’t have done them justice. So, I was happy for Brooklyn. They were taking a chance. I thought it was a really good trade. I thought it was good for us and where we were as a franchise. And I thought it was really good for Jet, Paul, and KG and for [new Nets coach] Jason Kidd. I didn’t know if they’d win a championship or not, because I knew Indiana and Miami were going to be very good, and I thought Chicago was going to be very good. But I really thought it was going to be a four-horse race in the East, with those four teams. That’s what it looked like to me when the season started.

How can trades be ultimately judged? Is it something that can happen immediately or does it have to play out over time?

Really, all you can go on is the information that you have and the reasons you do it at the time. Sometimes you’re making a trade to get a final piece to put you over the top. And sometimes you’re making trades that are trades along the way that you do that are going to lead to things down the road. We live in the economic climate of the NBA and the new CBA where luxury taxes are more penalizing, salary-cap management is very important. So, I think the trades, you can look at immediately, when they happen, as to why every team did them — and as I look at trades, they almost always make sense for all the teams involved. Every now and then, years down the road, a player becomes a way better player than he was when he was traded and a team looks better in a trade. But you can’t be worried about that. You’ve got to do what you think is best for your franchise at the time, whether it’s making a trade for the advantage of salary, or making a trade to project a younger player into a bigger role that would’ve been difficult had you not made a trade. There’s just a lot of factors that go into trades. But to me, most of the trades I’ve seen, in the NBA, because I respect the people in our business — they make sense. But there’s always some risk, when you’re dealing with people and players. People are capable of being injured. There’s always some risk.